The subject matter of the invention relates to a system or device for the centrifugation of samples comprising a rotor and at least one carrier having several uptakes for samples.
Dosing, mixing, tempering, filtering, closing, opening, washing, numbering, coding, retrieving, arranging and centrifuging are typical procedures when treating samples in laboratories. People endeavor to expedite those procedures by means of a convenient sample organization. Furthermore, they strive for a best possible automatization of the treatment of samples.
To achieve a common handling of the sample receptacles, there are already known chain-like systems using uptaking cylindrical receptacles. The uptaking cylinders are connected to each other by means of axially parallel swivelling joints allowing a chain-like movement around narrow radii, for instance in analyses devices. It's true that the chain simplifies the laboratory organization by facilitating the transportation, numbering, coding and retrieving of laboratory receptacles. However, charging of the receptacles presents a problem and in most cases, makes numerous manual sorting procedures indispensable. As to sample receptacles using a conventional sealing, the centrifugation makes an inclined or horizontal arrangement of the axis of a receptacle on the rotor necessary, which arrangement impairs the mass balance and may result in undesirable intermixtures after taking samples away and putting the chain upright again.
In principle, the sample receptacles may have a horizontal, inclined or vertical arrangement during centrifugation. There also do exist centrifuges with rotors using a swivel arm controlled by centrifugal force, so that the receptacles are vertically aligned as soon as the centrifuge stops, while they show an inclined or nearly horizontal alignment during centrifugation. In biochemical laboratories and in the microbiological field there are preferred rigid rotors where the laboratory receptacles are arranged at a slant angle of 45.degree.. On the one hand, the position of the samples in the centrifuge is of significance since the maximum way of sedimentation--which has an influence on the time of centrifugation and causes the precipitate to separate from the liquid as a result of the difference in density--depends thereon. A horizontal alignment of receptacles entails a maximum way of sedimentation, while a vertical alignment entails a minimum way of sedimentation. On the other hand, it proves to be relevant with respect to the accelerations during the centrifugation procedure, which accelerations, typically, may be equal to 15000 times the acceleration of earth. The cover seal is strained least by the sample when the receptacle is horizontally aligned and is strained most when it is vertically aligned. An inclined alignment of the receptacle might be a good compromise.
Up to now, laboratory centrifuges either had been charged manually or automatically by means of a special laboratory robot. It also became public knowledge to pre-charge the rotor manually or automatically and to connect it to the centrifuge thereafter. A partial charging, however, makes a symmetric mass distribution on the rotor necessary. These procedures are very troublesome and imperfect when choosing the manual way of operation and very time-consuming when preferring the automatization. An automatization of the centrifugation by simultaneously speeding up the procedure would be especially desirable with respect to repeated centrifugations without exchanging receptacles within one procedure. This, above all, is the case in the molecular biological field, for instance, when obtaining DNA from plasmids or bacteriophages. A periodic change between the dosing, mixing, centrifuging and tempering stations is characteristic for such a process.
Taking all this into consideration, the invention is based on the subject to produce a system for centrifugation favoring the treatment of samples in the laboratory field as well as the automatization thereof.